What You Should Know About Common Lung Diseases Including COVID-19

Breathing is the most vital part of your day. Without it, your organs wouldn’t function.

For many Americans, breathing is second nature. But, millions of people deal with lung diseases that affect the basic ability to inhale and exhale. We sought the help of Mark Rolfe, M.D., a lung transplant and critical care pulmonologist at INTEGRIS Baptist Medical Center, to shed more light on the most common lung diseases you need to know.

Explaining lung function

You take at least 17,000 breaths per day as part of a respiratory process that brings in oxygen and releases carbon dioxide. When you inhale, air flows down bronchi to each lung. From there, the air passes through smaller airways called bronchioles before reaching the alveoli and entering your blood. In a reverse process, carbon dioxide travels through those same channels for you to exhale.

Your lungs can take a beating from external factors, such as smoking or inhaling hazardous particles on the job. Other times, lung diseases are out of your control, either due to genetics, old age, allergies or asthma.

Hair-like projections called cilia line your airways to help prevent particles, ranging from bacteria to pollen, from entering your lungs. In the event of inflammation or irritation from an allergen, these airways tighten, which can lead to coughing or wheezing.

Inhaling smoke or other dangerous particles damage, and eventually kill, cilia to the point where they lose the ability to protect your lungs.

While you can take measures to stop smoking or protect yourself from occupational hazards such as silica and chemical fumes, you can’t remedy old age. Your airways weaken and become inelastic as you age, which can make it harder to breathe.

Obstructive lung diseases

Obstructive lung diseases affect how you exhale air. An obstruction in your airways leads to inflammation or swelling that makes it hard to release air from your lungs. As a result, your lungs contain more air than normal.

Common symptoms include shortness of breath and wheezing.

Asthma

Asthma is one of the most common lung diseases in the United States, affecting 26 million people. Inflammation in your airways constricts airflow to the alveoli and causes swelling and excess mucous secretions. In recent years, Dr. Rolfe says asthma is now accepted as a chronic condition that requires nasal medications such as adrenergic bronchodilators, anti-inflammatory nasal sprays or steroid nasal sprays.

“In the last decade, more and more emphasis has been placed on blocking the cells that release inflammatory mediators or the production of these mediators with drugs like leukotriene inhibitors and biologicals,” he says. “You treat asthma in a stepwise fashion, starting off with minimal medication and increasing the dosage as the disease becomes more severe.”

Even with these advancements, asthma is still a serious lung disease. On average, about 10 Americans die each day from asthma, mainly from medical non-compliance or inadequate treatment.

Chronic Obstructive Pulmonary Disease (COPD)

COPD is a generic term for anything that causes airflow obstruction. As we’ve mentioned, your airways narrow due to inflammation, leading to decreased airflow, which means less oxygen to your body and a buildup of carbon dioxide. This explains why people with COPD suffer from shortness of breath.

Smoking leads to death in eight out of every 10 COPD cases. Second-hand smoke and other air pollutants can also lead to COPD.

It’s common to find emphysema and bronchitis used interchangeably with COPD, as they both involve airway inflammation. Think of COPD as a spectrum of respiratory illnesses, as most people fall somewhere on this line.

Emphysema

Smoking is the primary cause of emphysema, which makes it a form of chemically-induced airway inflammation. This lung disease deteriorates the alveoli over time and leads to a large air pocket that restricts oxygen movement and makes it difficult to breathe.

Chronic Bronchitis

Another form of inflammation, bronchitis impacts the bronchi and causes mucous gland hypersecretion, airway narrowing, low sputum production, and, in severe cases, low oxygen and high carbon dioxide levels. You can develop temporary, acute bronchitis from bacteria or viruses that lasts a week or two. Chronic bronchitis primarily stems from smoking or other pollutants and lasts at least three months per year for two consecutive years. You’ll have trouble breathing and may experience chest pain, wheezing and mucus secretion.

Cystic Fibrosis

Cystic fibrosis differs from many other lung diseases in that it’s an inherited disorder — and not something you acquire — caused by a gene mutation at birth.

In healthy individuals, the cystic fibrosis transmembrane conductance regulator (CFTR) gene regulates how salt moves in your cells to produce thin liquids in the form of mucus, sweat and digestive juices. A defect in this gene leads to thicker liquids that become sticky. As a result, the airways in your lungs can become clogged or obstructed, leading to a wet (mucous) cough, wheezing and an increased risk of lung infections.

Restrictive lung diseases

Whereas obstructive lung diseases impact how you exhale, restrictive lung diseases impact your ability to inhale air due to a decreased lung capacity. Problems arise when inelasticity or a restriction from the chest wall make it difficult to take a full, deep breath.

Pneumonia

Pneumonia involves a serious infection or inflammation in your lungs that causes air sacs to fill up with pus and other liquids. Many bacteria and viruses cause pneumonia, and it can be difficult to treat in older adults.

Dr. Rolfe notes you may be more prone to usual interstitial pneumonitis (UIP) once you reach the age of 50. This disease involves the progressive scarring of the lungs that results in low oxygen and high carbon dioxide levels. In addition, it can cause the right side of your heart to fail due to pulmonary hypertension (high pressure in the vessel that goes to the alveoli) and lead to death.

There are two medications that slow scarring caused by UIP (Ofev and Esbriet) but neither cure the disease, and a lung transplant becomes the only option. Lung transplants may involve replacing one or both of your lungs. The good news is lung transplants are an option for almost all ages, ranging from newborns to older adults up to the age of 75. The INTEGRIS Nazih Zuhdi Transplant Institute is one of the largest and most experienced transplant centers in the U.S. Check out one of their latest lung transplant success stories.

Interstitial lung diseases

This umbrella term includes various types of lung diseases that cause scarring (fibrosis) in your lungs. Normally, your body produces tissue to repair lung damage. An interstitial lung disease causes an overproduction of tissue that will scar and thicken, which leads to breathing issues due to inadequate oxygen in your bloodstream.

Interstitial lung diseases start with inflammation in your bronchioles, alveoli or small blood vessels. Shortness of breath is the most common symptom, and you’ll also experience a cough and chest pain. Asbestosis, hypersensitivity pneumonitis and pulmonary fibrosis are some of the most common interstitial lung diseases. 

Lung cancer

Long-term exposure to harmful substances from smoking (cigarettes, cigars or pipes), radon gas or other pollutants can lead to cell mutation in your lungs. These cells can grow uncontrollably and form a tumor.

There are a handful of lung cancer types that fall under the following two categories:

Small cell lung cancer (SCLC)

• Small cell carcinoma: A fast-growing type of cancer that spreads quicker than non-small cell lung cancer.
• Combined small cell carcinoma: This type of lung cancer combines small cell carcinoma with additional characteristics of non-small cell lung cancer.

Non-small cell lung cancer (NSCLC)

• Adenocarcinoma: You’ll find this cancer on the outer part of the lung.
• Squamous cell carcinoma: You’ll find this cancer in the center of the lung next to the bronchus.
• Large cell carcinoma: You’ll find this fast-growing cancer in any part of the lungs.

Both of these types of lung cancer are common in men and women, accounting for nearly 25 percent of all cancer deaths. The American Cancer Society estimates more than 228,000 new cases in 2020 (116,300 in men and 112,520 in women). Lung cancer develops later on in life, mainly in people who are 65 or older.

How COVID-19 affects your lungs

Modern medicine has seen many different respiratory diseases affect the lungs. Whether it’s more complex strains of the influenza virus or coronaviruses that led to health crises such as Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS), these diseases cause lung infections that make it difficult to breath and can become deadly in severe cases.

The most recent example comes from coronavirus disease, more widely known as COVID-19. Dr. Rolfe explains how the coronavirus attaches to angiotensin receptors as a way to enter the cells, take over the genetics of the cell to replicate itself and then kills the cell.

“This systemic disease activates multiple inflammatory pathways, which results in blood clotting, low blood pressure, renal failure and heart inflammation,” he says. “The virus lights a (proverbial) fire and the impending result destroys your body. This is known as a “cytokine storm.”

These symptoms show up primarily in older adults and people with compromised immune systems. In certain cases, healthy individuals can experience lung issues and a severe lack of oxygen without even being aware of their situation. This phenomenon, known as happy hypoxics or silent hypoxics, happens when you can tolerate lower oxygen levels without knowing you’re causing any harm.

“Normally, the body gets oxygen by increasing the rate that blood carries oxygen to the tissue and increases the amount of oxygen that is removed from each hemoglobin molecule,” Dr. Rolfe says. Eventually, the tissues can’t get enough oxygen and lactic acid forms. This drives the respiratory center in the brain to breathe harder and the patient becomes short of breath.”